This can be used by targets to provide code sequences for cases that don't fit the target's parameters for simple loads/stores and can be more efficient than using a library call. This function can return a null SDValue if the target declines to use custom code and a different lowering strategy should be used.

If AlwaysInline is true, the size is constant and the target should not emit any calls and is strongly encouraged to attempt to emit inline code even if it is beyond the usual threshold because this intrinsic is being expanded in a place where calls are not feasible (e.g. within the prologue for another call). If the target chooses to decline an AlwaysInline request here, legalize will resort to using simple loads and stores.

If not DWORD aligned, it is more efficient to call the library. However if calling the library is not allowed (AlwaysInline), then soldier on as the code generated here is better than the long load-store sequence we would otherwise get.

This can be used by targets to provide code sequences for cases that don't fit the target's parameters for simple stores and can be more efficient than using a library call. This function can return a null SDValue if the target declines to use custom code and a different lowering strategy should be used.